CN113396360A

CN113396360A - Electro-active lens assembly

Info

Publication number: CN113396360A
Application number: CN202080012006.4A
Authority: CN
Inventors: 菲利普·埃克尔斯; 沃特·韦斯滕博尔格斯; 杰莱·德斯梅特
Original assignee: Morrow Public Ltd
Current assignee: Morrow Public Ltd
Priority date: 2019-01-30
Filing date: 2020-01-30
Publication date: 2021-09-14
Anticipated expiration: 2040-01-30
Also published as: CN113396360B; EP3918416A1; JP2022519062A; WO2020157245A1; NL2022478B1; US20220107510A1; KR20210121176A

Abstract

The present disclosure relates to an electro-active lens, a method of manufacturing the same and a pair of spectacles comprising at least one electro-active lens forming a stack of at least three elements, wherein: the first transparent body is a first lens element having a first optical axis, and the second transparent body is a second lens element having a second optical axis; at least one lenticular foil sandwiched between the first and second transparent bodies comprises a first transparent electrode, a second transparent electrode and a fresnel lens and liquid crystal material between the first and second transparent electrodes to define an optical arrangement, wherein the first and second transparent electrodes are electrically coupled to the terminals and configured to receive a voltage for operating the switchable lens, wherein the first and second conductive plugs are positioned with respect to an optical axis of the fresnel lens such that radial lines extending from the optical axis of the fresnel lens to the first and second conductive plugs enclose an angle of less than 120 degrees, preferably less than 90 degrees, more preferably less than 60 degrees with each other.

Description

Electro-active lens assembly

Technical Field

The present disclosure relates to a lenticular foil comprising: a first substrate having a first transparent electrode, a second substrate having a second transparent electrode, and a Fresnel lens (Fresnel lens) and a liquid crystal material between the transparent electrodes, wherein the transparent electrodes, the Fresnel lens and the liquid crystal material define an optical device having an optical axis in at least one state of the optical device.

The present disclosure also relates to a method of manufacturing an electro-active lens system forming a stack of at least three elements, the stack comprising a first transparent body, a second transparent body and a lens foil, the method comprising the steps of: at least one lenticular foil is provided onto the first transparent body and a second transparent body is provided onto the at least one lenticular foil.

The disclosure also relates to the resulting electro-active lens system and to a pair of spectacles comprising at least one electro-active lens system.

Background

An ophthalmic lens is a product customized for a particular user, the lens being shaped to fit the frame of a pair of spectacles such that the optical center is in front of the pupil of the user during use. The placement accuracy of an ophthalmic lens may be particularly important for progressive lenses and less important for bifocal lenses. In the case of an electronic eyewear device comprising a switchable lens of finite size embedded in a lens, substantially the center of the switchable lens is accurately positioned with respect to the position of the pupil of the wearer of the glasses. Thus, each lens must be customized for the wearer with respect to both the height and lateral position of the switchable lens center.

To address this drawback, EP 2405295 a1 discloses a composite lens assembly. Herein, an electro-active lens is present between a first glass and a second glass or plastic substrate. The cell is again present between two further transparent bodies, suitably configured as lenses or lens halves. The contact extends through one of these substrates and to a driver chip mounted to the outer surface of the unit. Furthermore, a patterned conductive layer is present on the outer surface. Additional contact pads are defined in the same conductive layer and are used to connect terminal leads that extend laterally away from the cell to opposite contacts of the battery. In order to integrate the composite lens assembly into eyeglasses, edging, i.e., removing material from the edge, is believed to be required to make the lens assembly fit into the eyeglasses. Furthermore, the application proposes that the two transparent bodies have a larger diameter than the lens unit or that additional spacers are present laterally of the lens unit.

As illustrated in this application, the electro-active lens may comprise polarization dependent nematic or cholesteric liquid crystals. In the former case, two cells need to be stacked and oriented at a 90 degree angle to eliminate the birefringence effect. In the latter case, only one unit is required.

However, said patent application does not specify how to establish a reliable contact of the electro-active lens unit. A plurality of vertical interconnects is shown in figure 1 of said application. However, this has the following disadvantages: such through holes are not transparent and therefore interfere with the view of the user of the glasses. The presence of the driver chip on the surface of the lens unit causes further interference. However, a technical problem is that patterning the electrodes requires several voltages to produce the desired optical effect. As explained in paragraph [0038] of said patent application, phase winding may be used to reduce the number of contacts required, but this also does not simplify the driver. Thus, it would be desirable to still require multiple vias.

An improved lens unit is known from EP3255479a 1. The lens unit includes a fresnel lens. This enables to design a lens unit with a small number of electrical connections. Furthermore, a polymer substrate is used, allowing the lens unit to be bent as desired. However, said patent application does not provide any information about the integration of the lens unit into the glasses. This is highly desirable because an efficient integration reduces costs overall. Moreover, users are keen on the design of eyewear, and an efficient integration may leave more design freedom for eyewear designers.

Disclosure of Invention

It is therefore a first object of the present disclosure to provide an electro-active lens system which allows a high degree of customizability of the lens layout and which is still reliable with respect to the contact portions.

It is another object of the present disclosure to provide a method of manufacturing such a lens system that allows for a high degree of customizability of the lens layout, while still preferably relying on readily available equipment and techniques in the ophthalmic industry.

It is a further object to provide an improved lens foil suitable for manufacturing such a lens system.

According to a first aspect of the present disclosure, there is provided a lenticular foil comprising a first substrate having first transparent electrodes, a second substrate having second transparent electrodes, and a fresnel lens and liquid crystal material located between the transparent electrodes, wherein the transparent electrodes, the fresnel lens and the liquid crystal material define an optical arrangement having an optical axis in at least one state of the optical arrangement. Herein, the lenticular foil further comprises a first conductive plug and a second conductive plug extending through the lenticular foil, wherein the first conductive plug and the second conductive plug are positioned relative to the optical axis of the fresnel lens such that radial lines extending from the optical axis of the fresnel lens to the first conductive plug and the second conductive plug enclose an angle of less than 120 degrees, preferably less than 90 degrees, more preferably less than 60 degrees with each other.

According to a second aspect of the present disclosure, a stack of a first lenticular foil and a second lenticular foil of the present disclosure is provided.

According to a third aspect of the present disclosure, a method of manufacturing an electro-active lens system forming a stack of at least three elements, the stack comprising a first transparent body, a second transparent body and a lens foil or a stack of lens foils according to the present disclosure is provided. The method comprises the following steps: (1) providing at least one lenticular foil on a first transparent body; (2) providing a second transparent body on the at least one lenticular foil; (3) generating at least one axial surface extending at least substantially parallel to a plug axis in the first and second conductive plugs, (4) applying an auxiliary conductive material that directly contacts the at least one axial surface of the conductive plugs, and (5) providing a conductive element configured for transmitting a voltage for operating an optical device connected to the auxiliary conductive material.

According to a fourth aspect of the present disclosure, an electro-active lens system is provided, the lens system forming a stack of at least three elements, wherein a lens foil or a stack of lens foils is sandwiched between a first transparent body and a second transparent body, wherein the conductive plugs have a plug axis extending substantially perpendicular to the transparent electrodes, and each of the conductive plugs is provided with an axial surface extending at least substantially parallel to the plug axis, at which axial surface the conductive plugs each contact an auxiliary conductive material connected to a conductive element extending out of the stack.

According to a fifth aspect, there is provided a pair of spectacles comprising an electro-active lens system as disclosed herein.

The present disclosure facilitates an efficient integration of a lens foil of the type mentioned in the opening paragraph into a lens system. A conductive plug extending in an axial direction (i.e. perpendicular to the transparent electrode) is used. Instead of applying an additional conductive layer on the outer surface of the lens foil or the electro-active lens, the method utilizes the axial surface of a conductive plug defined in the lens foil to establish contact with an auxiliary conductive material extending outside the lens system. The inventors have appreciated that the axial surface may be electrically contacted, for example by a conductive adhesive. In addition, the conductive plug is large enough to form a hole therein and/or laterally contact the conductive plug to expose such axial surface. Furthermore, according to the above aspect of the present disclosure, the conductive plugs are positioned on the same side of the fresnel lens, in other words, the optical axes enclose an angle of less than 120 degrees, preferably less than 90 degrees, more preferably less than 60 degrees with each other with respect to a radial line of the conductive plugs. This location of the sides eliminates the need for long wiring within the glasses. In one implementation, such wires (i.e., conductive elements) may even be integrated into a single connector device, such as a flex circuit.

In a preferred embodiment, a stack of a first lenticular foil and a second lenticular foil is present between the first transparent body and the second transparent body. More preferably, the liquid crystal material in the lenticular foils is a nematic liquid crystal material, and the optical arrangement of the first lenticular foil and the optical arrangement of the second lenticular foil enclose an angle of 90 degrees with each other to eliminate the effect of birefringence. In this way, the polarization dependence of the individual optical devices is corrected by the second optical device. This implementation is suitable for the manufacture of a pair of spectacles, wherein the lenses are defined in both the lens foil and the transparent body. Alternatively, a single lens foil is sufficient for sunglasses, the polarizer of which is used to eliminate the birefringence effect of the optical arrangement.

In a particular embodiment of the lenticular foil stack, the first lenticular foil and the second lenticular foil are assembled to each other such that the plug axes of the first conductive plugs of the two lenticular foils are aligned. In another implementation, the plug shafts may also be electrically connected to each other, for example, by conductive glue. This implementation seems to be advantageous for manufacturing. The electrode layers in the center of the stack of the first lenticular foil and the second lenticular foil may be contacted via one conductive plug. Therefore, it is not necessary to ensure electrical isolation of the electrode layer of one optical device from the electrode layer of another optical device.

Furthermore, the plug axes of the second conductive plugs of the two lenticular foils may also be aligned and may be electrically connected. Since the electro-active lens is preferably driven by an alternating current, there is no real distinction between the input electrodes and the output electrodes. This implementation also ensures that the conductive plugs are combined, enabling the stack of the first and second optical devices to be driven as a single optical device. Furthermore, this minimizes the number of conductive plugs, thereby minimizing visual impact.

In another implementation, the conductive plug is fabricated after stacking the first lenticular foil and the second lenticular foil. This reduces the number of perforations to be filled with conductive material, which is advantageous in terms of production costs.

In an advantageous embodiment of the method, the lenticular elements of the transparent body, for example the lens halves (lenses) and the optical means in the lenticular foil, may be arranged in imperfect alignment, or more precisely, wherein the optical axis of the lenticular foil differs from the common optical axis of the first and second lenticular elements. This embodiment takes advantage of the modularity of the lenticular foil and method: the conductive plug with its axial surface enables to create an effective contact after assembly of the lens system. Thus, this method allows the use of highly customizable and modular methods for manufacturing active eyewear devices.

The method behind the method described herein allows the use of lens halves manufactured using commercially available ophthalmic equipment. Thus, in one particular embodiment, the first and second lens elements are produced using a common design and are only customized during the assembly process to fit the lens system to the frame or the desired shape of the eyewear. More specifically, it is desirable to create holes in such lens elements to provide access to the conductive plugs. Milling, drilling, ablation, etching or any other suitable removal technique known per se may be used. Milling of the lens assembly is preferred because milling can be carried out using equipment and procedures conventional in the ophthalmic industry. Thus, in a preferred implementation, the method further comprises: the first, second and at least one lens foil are milled along the periphery of the cut-out region corresponding to a shape corresponding to the shape of the frame into which the electro-active lens is to be fitted.

In addition to facilitating different levels of assembly, it was observed that the method also facilitates repair and replacement of parts of the pair of spectacles comprising electro-active lenses (i.e. lens foils). For example, the glasses, frame, and/or electronics can be easily exchanged and replaced. Furthermore, the inventors have the insight that the fixed contact with the axial surface is more reliable than the known method. This fixed contact is not sensitive to mechanical vibrations, moisture fouling. Thus, the contacting will be reliable and may be performed under various assembly conditions outside the control of the lenticular foil manufacturer.

In different embodiments of the method according to the present disclosure, the axial surface is produced perpendicularly through the at least one lenticular foil and at least one of the first and second lenticular elements, or transversely (i.e. laterally) through the at least one lenticular foil and optionally (but typically also partially) through at least one of the first and second transparent bodies. The resulting hole or hole will expose the axial surface and an auxiliary conductive material may be applied to the axial surface.

In embodiments where the holes are arranged vertically, it seems advantageous to apply a conductive liquid or paste into the holes and to make a connection to another conductive element, such as a wire or a flexible circuit, outside the first or second transparent body. Although it is considered preferable to form the holes through the at least one transparent body and the at least one lenticular foil at once, it is not excluded that the holes in the transparent body are formed separately from the holes in the lenticular foil. Furthermore, the hole of the transparent body may have a different shape (e.g. truncated cone) or a different diameter than the hole through the lenticular foil. Furthermore, holes through the transparent body may be applied before assembling the lenticular foil with the transparent body.

In embodiments where the holes are arranged laterally, it seems preferable to assemble the wires or flexible circuits into the holes and establish contact with the conductive plugs by some conductive adhesive. However, it is not excluded that the lateral hole will be at least partially filled with a conductive material, such as a conductive adhesive. The transverse holes or bores may herein constitute conductor channels into which the conductive elements extend. The holes may have a substantially cylindrical shape, with a circular or elliptical cross-section. The bore may additionally be at least partially shaped as a truncated cone. The shape of the diameter that increases with distance from the conductive plug may be advantageous to facilitate assembly of the conductive element. Preferably, the bore has an orientation comprising an angle of 30 to 150 degrees, preferably 60 to 120 degrees or even 75 to 105 degrees to the plug axis of the conductive plug. More preferably, the holes do not extend through the exposed major faces of the first and second transparent bodies. In other words, an oblique orientation is not excluded. Such an inclination angle may be advantageous in view of the desired position of the conductive element outside the system with respect to the lenticular foil. For the sake of completeness, it is observed that such holes or conductor channels may in principle only be present in the at least one lenticular foil. However, in view of the foreseeable dimensions of the lenticular foil and the conductive elements, in most embodiments the holes will also extend through at least one of the transparent bodies.

For the sake of clarity, it can be seen that the term "at least substantially perpendicular to the transparent electrodes" refers to an orientation that is generally perpendicular, but may deviate from exactly perpendicular due to any manufacturing tolerances. In case the transparent electrode connected to the conductive plug is not planar, this is related to the orientation of the transparent electrode in the area of the conductive plug. The term "at least substantially parallel to the plug axis" relates to an orientation comprising an angle of at most 30 degrees relative to the plug axis. It is foreseen that the axial surface is created by providing holes in a direction substantially parallel to the plug axis or in a direction substantially perpendicular to the plug axis. However, it is not excluded that such holes are provided by a specific oblique orientation and that the holes comprise an angle of at most 30 degrees. The term "radial position" refers in the context of the present application to a position in a plane parallel to the transparent electrode. The terms "first lens element" and "second lens element" may refer to separate lenses in the context of the present application, but are preferably cooperating lens elements. Such cooperating lens elements are also referred to as lens halves (lenses). It is observed that the transparent body preferably constitutes a lens half. However, it is not excluded that at least one of the transparent bodies will be a body (or plate) without any optical function. Depending on the diopter of the glasses. The term "conductive element" refers to any contact element that extends outside the lens system. The conductive element may be provided with contact pads on its exterior, but may alternatively be provided with only ends or contact pads electrically coupled to the conductive circuit of the lens system. Typically, this is also referred to as a terminal in the context of the present application. With respect to the optical axis of the lens foils, it is observed that at least one lens foil preferably does not substantially contribute to the optical power of the lens system in one of its states (on or off). Thus, the optical axis is structurally defined as the center of the fresnel lens. The term "tune" is understood in the context of this application to refer to the relative orientation of two or more elements. For example, how the optical axis of the at least one lenticular foil is oriented/aligned with respect to the first optical axis and/or the second optical axis of the first and second lenticular elements. It can be seen that the optical axes of the lenticular foils may be oriented parallel to the common optical axis, but this is not essential. For example, different orientations can be achieved by cropping the lenticular foil. For the sake of clarity, it is observed that the terms "electro-active lens", "optically switchable lens" and "tunable lens" are used as alternatives to "optical device" in the context of the present disclosure. Furthermore, in the context of the present application, the term "radial direction" is used for a direction extending radially from the optical axis of the fresnel lens. A more specific implementation of "radial" is "lateral", which defines an orientation at or towards a lateral side of the lens foil and/or the lens system.

Preferably, the method further comprises: the first and second transparent bodies and the at least one lens foil are cut along the outer circumference of a cut-out area having a shape corresponding to the shape of the frame in which the electro-active lens is to be fitted.

The alignment may be performed using at least one alignment element and a first transparent body, a second transparent body (i.e. a first lenticular element and a second lenticular element) and corresponding alignment holes in at least one lenticular foil. The alignment holes in the first and second transparent bodies and in the at least one lens foil may each be positioned in a portion of the respective first and second transparent body and at least one lens foil outside the cut-out region, i.e. the region of the lens system to be (at least partially) cut out to meet the desired shape of the spectacle frame or spectacles. Thus, the alignment holes may not affect the finished electro-active lens, as the alignment holes may be located at positions to be removed before the finished electro-active lens system is finished. In particular, the alignment holes are positioned using, for example, a computer-implemented method that facilitates accuracy. The at least one alignment element is, for example, an alignment pin to be inserted into the alignment hole.

Alignment marks may be applied instead of using alignment holes. Such alignment marks are optical structures defined in the element during production, e.g. simultaneously with providing the first and second transparent bodies with shapes. At least one of the conductive plugs may also be used as an alignment mark, i.e. by specifying a standardized distance between the at least one of the conductive plugs and the optical axis of the electro-active lens. Alternatively or additionally, alignment marks may be produced in the at least one lenticular foil as a pattern in the conductive layer (preferably the conductive layer is applied on the transparent electrode layer in one or more selected areas), or as auxiliary conductive plugs in areas laterally outside the cut-out area.

Preferably, a plurality of alignment holes or alignment marks are provided to ensure alignment of the lens elements in various directions. For example, using two alignment holes or alignment marks will fix the alignment in the radial direction and the angle of the element with respect to the other element in the radial plane (i.e. parallel to the transparent electrode). Optionally, the axial direction is fixed by other elements arranged adjacent (in the axial direction) to the element.

Thus, the correct mutual alignment of the first lenticular foil, the second lenticular foil and the at least one lenticular foil may be different for different users. Preferably, the common optical axis corresponds to a pupil position of an eye of a user of the pair of glasses when the user is gazing at infinity. The optical axis of the optical means in the at least one lenticular foil corresponds to the pupil position of the user's eye of a pair of spectacles where the user needs to correct the position of the presbyopia of the user's eye. For example, when the adjustable lens is used for reading only, the axis may be positioned horizontally at the user's pupillary distance minus 2 to 4 millimeters to compensate for the convergence of the eyes. Vertically, it is preferable to set this position as low as possible in the frame.

The lenticular foil preferably comprises a first conductive layer disposed on and electrically coupled to the first transparent electrode, and a second conductive layer disposed on and electrically coupled to the second transparent electrode. Herein, the first conductive layer and/or the second conductive layer will have a larger thickness in the axial direction of the lens than the first transparent electrode and/or the second transparent electrode, respectively. Due to the additional conductive layer provided on the electrodes, a reliable electrical connection can be obtained while providing modular design options. In particular, the conductive layer has an interface with the conductive plug. The interface area of the interface is large enough to ensure proper contact, i.e. contact with acceptably low contact resistance and good reliability. When there is more than one optical device, each electrode is provided with a respective conductive layer.

Suitably, there is no conductor layer in the functional areas where the fresnel lens is present, as the conductor layer is typically opaque or not completely transparent. According to a preferred embodiment, the conductor layer is patterned in a plurality of patterns, each pattern having a relatively small surface area (e.g. compared to the size of the conductive plugs). Thus, the visual impact of the opaque conductive layer can be minimized. The shape of the conductor layer pattern is open for further design and optimization. The conductive layer may be elongated and/or repeated in areas over the respective conductive areas. The conductive layer may comprise one or more sub-elements, thereby minimizing the visual impact on the lens stack, while the total surface area of the conductive layer remains relatively large. As a result, the risk of forming a perforation defining a conductive plug without passing through the conductive layer is significantly reduced. The one or more sub-elements may be, for example, a plurality of rings, a stripe pattern, a mesh pattern, a repeating pattern, etc., as long as the visual impact is relatively small (i.e., the dimension in a plane perpendicular to the axial direction of the lens stack is relatively small). Examples of conductive patterns have been described in the non-prepublished application PCT/EP2018/082445 in the name of applicant, which is incorporated herein by reference.

In regions corresponding to positions of the first conductive plugs and/or the second conductive plugs, respectively, a portion of the second transparent electrode and/or the first transparent electrode may be removed. Removing a portion of the electrode opposite to the electrode connected to the conductive plug may prevent an undesirable short circuit between the electrodes. To this end, an additional electrical interruption in the counter electrode may alternatively or additionally be provided in the region where the conductive plug is electrically coupled to the electrode. Such an electrical discontinuity may be, for example, an etched away boundary line in the counter electrode, such that a portion of the counter electrode near a conductive plug coupled to the electrode is isolated from the rest of the counter electrode.

The lenticular foil may comprise at least one spacer arranged within the optical device. In varying cases, such as the non-limiting exemplary case where pressure is applied to the electro-active lens in its axial direction, such spacers may maintain a fixed distance between the electrodes of the optical device. In one implementation, a spacer is disposed between the fresnel lens and the opposing electrode. The spacer is preferably made of an optically transparent material. Since the fresnel lens generally includes a plurality of concentric structures, it is feasible to provide the spacer at a position where the visual disturbance is minimal.

The lenticular foil may further comprise an optically transparent, electrically insulating material arranged laterally of the fresnel lens and the liquid crystal material. Thus, the material is also configured as a tube for a liquid crystal material, preferably provided in the form of a liquid or paste. Such electrically insulating material may include structures configured to act as spacers, but this is not required. In a preferred implementation, the electrically insulating material is made of the same material as the fresnel lens to minimize visual impact. At least one spacer may be disposed within the interior volume of the optical device. The electrically insulating material may extend into the connection region where one or more conductive plugs may be disposed and may cover the conductive layer (if present). The material may be the same material as used in the functional zones and deposited simultaneously with the fresnel lens structure, but may alternatively be a separately deposited material. A method of manufacturing an electro-active lens has been described in EP3255479a1, which is incorporated herein by reference.

Preferably, the first and second substrates are flexible and made of a polymer material. Further preferably, the fresnel lens structure and any electrically insulating material in the at least one lenticular foil also comprise a polymer material. Fillers and/or additives dissolved or dispersed therein are not excluded, although it is strongly preferred that the electroactive lens is optically transparent. As discussed in the above mentioned application EP3255479, this allows the at least one lenticular foil to be thermoplastic in its entirety, which means that the lenticular foil can be bent to conform to the shape of the interface with the first lenticular element and/or the second lenticular element.

The first lens element used in the lens system may have a substantially flat surface, wherein the substantially flat surface of the first lens element may face the at least one lens foil, and wherein the second lens element may have a substantially flat surface, wherein the substantially flat surface of the second transparent body may face the at least one lens foil, and wherein the at least one lens foil may have two substantially parallel surfaces in an axial direction of the electro-active lens. So that the electro-active lens can be assembled in a modular manner.

Furthermore, the first lens element may have a convex surface and an opposite substantially flat surface, wherein the substantially flat surface of the first lens element may face the at least one lens foil, and wherein the second lens element may have a concave surface and an opposite substantially flat surface, wherein the substantially flat surface of the second transparent body may face the at least one lens foil, and wherein the at least one lens foil may have two substantially parallel surfaces in an axial direction of the optical device.

The convex surface and/or the substantially flat surface of the first lens element, and/or the concave surface and/or the substantially flat surface of the second lens element may be pre-treated. The surface may be pre-treated prior to assembly of the electro-active lens. For example, any of these surfaces may be pre-treated with at least one of: polarizing layers, polishing, anti-reflection layers, etc.

In the manufacturing method, the at least one lenticular foil may be provided as a prefabricated element. Preferably, the first and second transparent bodies may be provided as prefabricated elements.

At least one passivation layer may be present in a region of the lens system in which the conductive element may be coupled to the conductive plug. Thereby, a smooth outer edge may be obtained, which is preferred from a user point of view. Furthermore, this may also be preferred from a device perspective, as the passivation layer may reduce negative optical effects caused by the steps required to couple the electrical connections (e.g., creating an optical interface between materials of different refractive indices). To this end, the passivation layer is preferably formed of a material having similar optical properties as the first lens element and/or the second lens element.

In some embodiments, the first transparency is connected to the second transparency using an adhesive. More specifically, the adhesive may extend along at least the lenticular foil from the first transparent body to the second transparent body. The adhesive may be present therein, for example, in a glue channel through the at least one lenticular foil and/or along at least a portion of a peripheral edge of the at least one lenticular foil. It has been demonstrated that such adhesive attachment improves the overall stiffness and mechanical stability of the lens system. In particular, due to the presence of one or more lenticular foils of layered construction between the transparent bodies, shear forces act on the layers within one or more lenticular foils or between two lenticular foils (in case of more than one lenticular foil). This force is counteracted in an effective manner by the adhesive connection.

Preferably, there is an adhesive connection in addition to the adhesive on the opposite main face of the at least one lenticular foil. Due to the adhesive present between the first and second transparent bodies, the first and second lens elements do not have to be coupled to join the two elements, e.g. with a screw and nut coupling. Thus, the visual impact on the lens element may be relatively small. For applying the adhesive both on the main face and for applying the adhesive connection or connections, the adhesive is preferably applied in liquid form, for example as a paste, as a dispersion or as a solution. More preferably, the adhesive is dispensed along the peripheral edge and/or in the glue channel. However, it is not excluded that the adhesive is provided on a main face of the lenticular foil and thereafter flows along the edges through the lenticular foil and/or into the glue channels. For such flow, it is not excluded to increase the temperature to reduce the viscosity of the adhesive.

In an advantageous embodiment, the lenticular foil is cut into a predetermined shape, wherein said shape comprises glue channels along one or more portions, which are to subsequently form the peripheral edge of the lenticular foil. Thereafter, the part of the lenticular foil on the other side of such glue channel, except for the fresnel lens, may be removed, so that the adhesive connection will be located along the peripheral edge of at least one lenticular foil. The removal of said portions may for example be performed in a removal step in which the entire lens system (and thus the transparent body and the intermediate lens foil) is provided with the desired shape. However, alternatives to remove these portions are not excluded.

Preferably, the cutting into a predetermined shape, also called edging, is performed before the at least one lenticular foil is provided on the first transparent body. Thus, the partial removal of the at least one lenticular foil may result in one or more glue channels extending along an axial direction of the at least one lenticular foil and which may be configured to receive the adhesive. Thereby, the first and second transparent body may be integrally connected, thereby sandwiching the at least one lenticular foil between the first and second transparent body.

Preferably, only some connecting portions remain in the area where the adhesive is applied, thereby externally sealing the switchable lens. Preferably, the connecting portion is relatively small, e.g. only 25%, preferably 5%, more preferably 1%, even more preferably < 1% of the total peripheral edge of the at least one lenticular foil is formed by such connecting portion, while the rest of the peripheral edge of the at least one lenticular foil is formed by the adhesive. Furthermore, in some embodiments, the at least one lenticular foil may be completely surrounded by the adhesive. The switchable lens can thus be sealed from external conditions.

In another implementation, said connection portions outside the cut-out area are advantageously used during the assembly process, for example for alignment and/or for placement and clamping by a device that may damage the at least one foil. The alignment occurs, for example, in an alignment hole. After assembly, such connecting portions may be removed.

In another embodiment, the lenticular foil is cut into a predetermined shape comprising glue channels extending between the first foil and the second foil portion. However, the predetermined shape is such that the glue channel does not become part of the peripheral edge of the lenticular foil.

For joining the first and second transparent bodies by means of an adhesive, although there is at least one lenticular foil between the first and second transparent bodies, it is a preferred option to provide glue channels through the at least one lenticular foil, which glue channels are to be filled with adhesive. It is considered feasible, but not excluded, to apply an adhesive that can be cured by uv radiation. More preferably, such adhesive is applied in the form of a paste or even a foil into the gluing channel. The adhesive may be applied before or after assembling the at least one lenticular foil to the first transparent body. Adhesives that become tacky upon mild heating, such as EVA (ethylene vinyl acetate) based adhesives, are considered advantageous when applied prior to assembly. This action allows for temporary securing of the adhesive which would otherwise run off. It is furthermore possible that the glue channel is provided with a laterally arranged inlet which passes through one of the transparent bodies or in the lenticular foil. This facilitates the application of the adhesive after assembly. When such a channel extends laterally, the visual impact can be minimized, since the channel does not enter the functional area of the device, i.e. the area defining the optical means opposite to the connection area provided with the conductive plug.

The removal of the first and/or second transparent body and/or the portion in the at least one lenticular foil is performed, for example, by drilling and/or milling. The same technique can be applied to edging the first and second transparent bodies and the at least one lens foil to the edge of the cut-out area to form a shape corresponding to the shape of the frame to be fitted with the lens.

The pair of glasses may further comprise a controller for controlling signals for switching the LC material in the optical device between at least a first state and a second state. Wherein in the first state the refractive index of the LC material (in the axial direction of the lens stack) may substantially match the refractive index of the fresnel element, and in the second state the refractive index of the LC material (in the axial direction of the lens stack) may be different from the refractive index of the fresnel element. The first optical axis may correspond to a pupil position of an eye of a user of a pair of glasses when the user gazes at infinity. The second optical axis may correspond to a pupil position of an eye of a user of the pair of glasses at a position where the user may need to correct a presbyopia of the user's eye.

Further features of the present disclosure will be set forth in the accompanying description of various exemplary embodiments thereof. In the description reference is made to the accompanying drawings.

According to another aspect, the present disclosure relates to a stack of mutually attached first and second lenticular foils, each lenticular foil comprising a first substrate with a first transparent electrode, a second substrate with a second transparent electrode, and a fresnel lens and a liquid crystal material between the transparent electrodes, wherein the transparent electrodes, the fresnel lens and the liquid crystal material define an optical arrangement. Herein, each lenticular foil further comprises a first conductive plug and a second conductive plug extending through the lenticular foil. The conductive plug may have a plug axis extending substantially perpendicular to the transparent electrode. Attached to each other means that the first lenticular foil and the second lenticular foil are not only separate entities but are combined into a single intermediate product.

The advantage of this stack is that it can be used to integrate an electro-active, refocusable lens into eyeglasses. The conductive plug facilitates contact after having been integrated with the transparent body (typically the lens halves) because the conductive plug is well visible. Further, the conductive plug may be exposed from any side (i.e., front, bottom, or side) according to design or the like. Furthermore, these conductive plugs are preferably arranged in a connection region outside the lens region in which the fresnel lens of the lenticular foil and any lens elements of the transparent body are located. Thus, the visual disturbance is limited to a minimum. Such a stack and the lenticular foil therein may have any of the preferred embodiments and implementations discussed above with reference to the first aspect. For example, the liquid crystal material of the first lenticular foil and the second lenticular foil is preferably a nematic liquid crystal material, and wherein the optical arrangement of the first lenticular foil is oriented at an angle of 90 degrees with respect to the optical arrangement of the second lenticular foil to avoid birefringence.

In an embodiment, the conductive plugs of the first and second lenticular foils are oriented such that the axes of the first conductive plugs of the two lenticular foils are aligned, and wherein the first conductive plugs are electrically connected to each other. In a further embodiment, the axes of the second conductive plugs of the two lenticular foils are aligned and wherein the second conductive plugs are electrically connected to each other. This facilitates ac driving of the optical device, as described above.

It is also advantageous to position the first and second conductive plugs relative to the optical axis of the fresnel lens such that radial lines extending from the optical axis to the first and second conductive plugs enclose an angle of less than 120 degrees, preferably less than 90 degrees, more preferably less than 60 degrees with each other.

The present disclosure also relates to the use of such a stack in an electro-active lens system. Most preferably, the lens system forms a stack of at least three elements, wherein the stack is sandwiched between a first transparent body and a second transparent body, wherein the first and second conductive plugs of the lens foil have plug axes extending substantially perpendicular to the transparent electrodes, via which the lenses are electrically coupled to the conductive elements extending out of the stack.

Preferably, the conductive plug is provided with an axial surface at which an auxiliary conductive material is present, the conductive element being connected to the auxiliary conductive material, wherein the auxiliary conductive material extends within a vertically or laterally arranged channel. Additional details herein have been explained and discussed above and will be further elucidated with reference to the drawings, and this embodiment with respect to this aspect of the disclosure is considered to be included as well.

In yet another aspect, the disclosure relates to an electro-active lens system, the lens system forming a stack of at least three elements, wherein at least one lens foil is sandwiched between a first transparent body and a second transparent body, and wherein the at least one lens foil comprises a first substrate having a first transparent electrode, a second substrate having a second transparent electrode, and a fresnel lens and a liquid crystal material between the transparent electrodes, wherein the transparent electrodes, the fresnel lens and the liquid crystal material define an optical arrangement, wherein the first transparent electrode and the second transparent electrode are each electrically coupled to conductive elements extending outside the lens system, wherein the lens foil further comprises a first conductive plug and a second conductive plug extending through the lens foil, the conductive plugs having plug axes extending substantially perpendicular to the transparent electrodes, and each of the conductive plugs being provided with an axial surface extending at least substantially parallel to the plug axes, at the axial surfaces, the conductive plugs each contact an auxiliary conductive material connected to a conductive element extending out of the stack, wherein the auxiliary conductive material extends laterally within the conductor channel from the axial surfaces, wherein preferably also a portion of the conductive element is present within the conductor channel.

Such a system may be manufactured by a method comprising the steps of:

providing at least one lenticular foil on a first transparent body;

providing a second transparent body on the at least one lenticular foil;

at least one axial surface is created in the first and second conductive plugs that extends at least substantially parallel to the plug axis,

providing an auxiliary conductive material directly contacting the at least one axial surface of the conductive plug and connected to the conductive element to electrically couple the first and second transparent electrodes to the conductive element, the conductive element configured to transmit a voltage for operating the switchable lens,

wherein the step of creating an axial surface comprises: creating a hole in the at least one lenticular foil, the hole extending into the first transparent body and/or the second transparent body, being oriented transversely with respect to the plug axis, and terminating in the first conductive plug or the second conductive plug, thereby defining an axial surface,

wherein preferably the conductive element is partially disposed in the aperture, thereby forming a conductor channel, and the conductive element is connected to the conductive plug by the auxiliary conductive material.

The use of a lateral connection to the lenticular foil via a conductive plug has proven to be a very practical assembly method. The location of the conductive plugs on one side of the lenticular foil in combination with it is particularly preferred as this allows assembly from one side.

According to yet another aspect, a method of manufacturing an electro-active lens system and such a lens system obtainable by the method are provided. As mentioned above, the lens system forms a stack of at least three elements, the stack comprising a first transparent body, a second transparent body and at least one lens foil in which an optical arrangement is defined, which generally has an optical axis. The lenticular foil comprises a first substrate having first transparent electrodes and a second substrate having transparent electrodes, between which transparent electrodes a fresnel lens and a liquid crystal material are present, the electro-active lens further comprising a first conductive plug and a second conductive plug extending through the electro-active lens, the conductive plugs having plug axes extending substantially perpendicular to the transparent electrodes. The method comprises the following steps: (1) providing at least one lenticular foil on a first transparent body; (2) an adhesive (3) is arranged on the at least one lenticular foil and a second transparent body is arranged on the at least one lenticular foil. Herein, the adhesive is arranged between the at least one lenticular foil and the second transparent body. The at least one lenticular foil is provided with at least one glue channel extending through the lenticular foil to extend from the first transparent body to the second transparent body after manufacture. An adhesive is disposed in the channel and cured to form an adhesive connection.

Additionally or alternatively, the at least one glue channel is arranged outside the area defining the optical device. This region is typically a connection region where a conductive plug is also present. In this way, no functional domain, i.e. lens region, is included.

In an advantageous embodiment, the method further comprises the steps of: the shape of the electro-active lens system is modified such that the glue channels filled with adhesive become part of the peripheral edge of the at least one lens foil. Such modifications typically require the removal of the outer portion.

Additionally or alternatively, there is at least one connection region extending outwardly from the cut-out region defined by the at least one glue channel away from the region defining the optical device. For example, alignment may be performed with the connection region extending outside the cut-out shape. In this case, the method further comprises the steps of: the at least one lenticular foil is aligned with at least one of the first and second transparent bodies and/or the further lenticular foil by means of alignment means in the connection region, wherein the alignment means are, for example, at least one alignment hole.

It will be seen that any of the descriptions given above in respect of one aspect also apply to the other aspect. Furthermore, unless expressly stated otherwise, any embodiment specified in respect of one aspect is also applicable to another aspect.

Further details of the disclosure follow the following description of some embodiments of the disclosure. In the description, reference is made to the accompanying drawings, in which:

FIGS. 1A and 1B are front views of an eyeglass frame including an electro-active lens and electrical connections coupled to the electro-active lens;

fig. 2A illustrates a method of integrating an optical device into two lens elements.

Fig. 2B and 2C show a method of integrating more than one lenticular foil between two transparent bodies realized as lenticular elements;

FIGS. 3A and 3B each show a lens stack from a side view and a top view;

fig. 4A to 4D illustrate a method of producing an electro-active lens system;

fig. 5A to 5D illustrate a method of producing an electro-active lens system;

FIG. 6 shows the optical axes of the lenses in the eyeglass frame;

fig. 7 shows the lenticular foil before it is integrated between the first and second transparent bodies;

FIG. 8 illustrates the relative alignment of the optical axis of the optical device and the optical axes of the first and second lens elements;

fig. 9 shows an integration process of a lenticular foil between a first transparent body and a second transparent body;

fig. 10 shows an integration process of a lenticular foil between a first lenticular element and a second lenticular element using an alignment means;

figure 11 shows the completed electro-active lens system from a front view and a side view;

fig. 12A and 12B illustrate further embodiments of an electro-active lens 1 according to embodiments of the present disclosure, for example an electro-active lens as manufactured by a method according to the present disclosure; and

fig. 13A and 13B show an embodiment of an external connector as mentioned in the context of fig. 12A and 12B.

Detailed Description

In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. It will be apparent, however, that the present disclosure may be practiced without these specific details. In other instances, well-known structures and devices are not described in exhaustive detail to avoid unnecessarily obscuring the present disclosure.

It will be apparent to those of skill in the art upon reading this disclosure that each of the individual embodiments described and illustrated herein has discrete components and features which may be readily separated from or combined with the features of any of the other several embodiments without departing from the scope of the present disclosure. Any recited method may be performed in the order of events recited, or in any other order that is logically possible.

It should also be noted that, as used herein and in the appended claims, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. It should also be noted that the claims may be drafted to exclude any optional element. As such, this statement is intended to serve as antecedent basis for use of such exclusive terminology as "solely," "only," etc., or use of a "negative" limitation in connection with the recitation of claim elements. The terms "transparent body" and "lens element" will be used to refer to the elements, since according to the illustration the transparent body is realized as a lens element. Similarly, the same reference numerals are used in the description to refer to both the lenticular foil and the optical device. Strictly speaking, an optical device is an optical function (e.g. a lens) defined in a lenticular foil.

Fig. 1A and 1B are front views of a pair of eyeglasses including an eyeglass frame 2. An electro-active lens 1 is arranged in the spectacle frame 2. The electro-active lens 1 is configured to correct the vision of a user of the pair of spectacles. For example, a user may have presbyopia and thus may need visual assistance for seeing a clear image. For some users of eyeglasses, a single optical intensity may not be sufficient and the eyeglasses may require, for example, bifocal lenses. Compared to a normal bifocal lens, an electro-active lens can provide two optical intensities within one lens. As will be explained later on, the optical intensity of the electro-active lens can be electrically changed by applying a voltage over the electrical connection 8. This allows the optical power of the fresnel lens structure 4 to be added to the optical power of the electro-active lens 1.

Due to the production method of the present disclosure, the design options for producing a pair of spectacles comprising an electro-active lens 1 are greatly increased. For example, the position of the electrical connection 8 may vary over a relatively large area of the electro-active lens 1, e.g. the connection 8 may be placed on the side of the electro-active lens 1, as shown in fig. 1A. Alternatively, the connection may be placed on top of the lens, as shown in fig. 1B. However, the location is not limited to the examples provided by fig. 1A and 1B. The ability to change the position of the electrical connections 8 enables the integration of the electro-active lens 1 into many different frames 2 without having to change the production method. The visual impact of the electrical connections 8 can also be reduced by appropriately positioning the electrical connections 8 according to the spectacle frame in areas of the electro-active lens 1 that are rarely used by the user, for example on the sides, top and/or bottom of the electro-active lens 1.

Furthermore, the position of the fresnel lens structure 4 can also be changed by the production method discussed later. Thus, the optical axis of the electro-active lens 1 and the optical axis of the fresnel lens 4 can be appropriately positioned with respect to the pupil position 3 of the user, according to the needs of the user.

Fig. 2A shows a method of integrating an optical device into two lens elements to obtain an electro-active lens 1. The electro-active lens 1 comprises at least three elements after assembly. The first transparent body 10 is a first lens element 11. The first lens element 11 may be made of an optically transparent material having a curved surface 12 and a flat surface 13, wherein the curved surface 12 is preferably convex. The first lens element 11 has a first optical axis O1. The second transparent body 20 is a second lens element 21. The second lens element 21 may be made of an optically transparent material having a curved surface 22 and a flat surface 23, wherein the curved surface 22 is preferably concave. The second lens element 21 has a second optical axis O2. In the example of fig. 2A, the first optical axis O1 and the second optical axis O2 are aligned on a common optical axis. The first lens element 11 and the second lens element 21 provide a first optical power of the electro-active lens 1.

At least one lenticular foil 30 is placed between the first transparent body 10 and the second lenticular elements 20. The at least one lenticular foil 30 is an optical device 31, e.g. an optically switchable lens, the optically switchable lens 31 being configured to be activated using a voltage supplied to the at least two optically transparent electrodes 32. The electrode 32 may be, for example, a tin-doped indium oxide (ITO) layer and/or an Indium Zinc Oxide (IZO) layer. A Liquid Crystal (LC) layer is disposed between the electrodes 32. The LC layer may comprise, for example, nematic and/or cholesteric liquid crystals. These liquid crystals are arranged in a closed volume 37 enclosed in a border (not shown) and within said electrodes 32. The border preferably comprises at least partially the same material as the fresnel lens to minimize visual interference. As discussed in EP3255479a1, it is believed preferable to apply an adhesive at the top side of the border to ensure that the second and first substrates of the lenticular foil are fixed. In addition, the optical device 31 comprises a fresnel lens structure 4. Within the volume 37, one or more spacers may be arranged. The spacer may be disposed between the fresnel lens 4 and the opposing electrode 32, and/or a spacer (not shown) may be disposed between the electrodes 32. The electrodes 32 are configured to change the alignment of the liquid crystal and thereby change the refractive index of the LC layer in the axial direction of the electro-active lens 1. Thereby, a variation of the optical power of the at least one lens foil 30 may be obtained.

For example, in the first state, no voltage is applied to the electrode 32. In this first state, the refractive index of the liquid crystal in the axial direction of the electro-active lens 1 matches the refractive index of the fresnel lens 4 (i.e., the passive lens 4). Thereby, the fresnel lens 4 and the LC layer effectively form an optical layer of the same refractive index having two parallel surfaces (in the axial direction of the at least one lenticular foil 30). Thus, light rays incident on the electro-active lens 1 will not be collimated or dispersed by the at least one lenticular foil 30. The light rays will be refracted by the optical power provided by the first lens element 11 and the second lens element 21. However, in the second state, when a voltage is applied to the electrodes 32, the liquid crystal is aligned due to an electric field generated between the electrodes 32. Due to this alignment, the refractive index of the LC layer in the axial direction of the at least one lenticular foil 30 changes, creating an optical interface between the liquid crystal and the fresnel lens 4 having a different refractive index than the liquid crystal. Due to the optical interface, light rays incident on the lenticular element 1 will be refracted by the at least one lenticular foil at the optical interface between the fresnel lens 4 and the LC layer, thereby collimating or dispersing the light rays incident on the fresnel lens 4. This will provide the electro-active lens 1 with an additional optical power than the first optical power provided by the first lens element 11 and the second lens element 21. Alternatively, the first state may be a state in which a voltage is applied to the electrodes 32 and no voltage is applied to the electrodes 32 in the second state, in which the refractive indices of the LC layer in the axial direction of the electro-active lens 1 are respectively matched to and different from the refractive index of the fresnel lens 4.

For the following description, the on state refers to a state in which the additional power is provided to the electro-active lens 1 by creating a refractive optical interface between the liquid crystal in the volume 37 and the fresnel lens 4, and the off state refers to a state in which the refractive index of the liquid crystal in the axial direction of the electro-active lens 1 matches the refractive index of the fresnel lens 4, and as a result of this matching, no additional power is provided to the electro-active lens 1 other than the first power provided by the first lens element 11 and the second lens element 21. Preferably, the refractive indices of the LC layer (in the off-state) and the fresnel lens 4 match the refractive indices of the first lens element 11 and the second lens element 21.

In the on state, additional optical power is provided in the region corresponding to the region in which the fresnel lens 4 is present. The fresnel lens 4 may be a positive fresnel lens or a negative fresnel lens, and preferably, the fresnel lens 4 is a negative fresnel lens. In the example of fig. 2A, the third optical axis O3 as the optical axis of the fresnel lens 4 coincides with the first optical axis O1 and the second optical axis O2. However, although the first optical axis O1 and the second optical axis O2 are aligned on a common optical axis, the third optical axis O3 may or may not coincide with the common optical axis. The third optical axis O3 is arranged with respect to the common optical axis according to the user's needs. The additional lens power due to the at least one lens foil 30 may be present only in the on-state, and thus the third optical axis O3 may correspond to a lens action only in the on-state. However, the third optical axis O3 corresponds to the optical axis of the fresnel lens 4 regardless of the state of the at least one lens foil. Which fresnel lens 4 is used may vary between users, for example, fresnel lenses 4 of different sizes, intensities, shapes may be used, and the fresnel lens 4 may be positive or negative, depending on the needs of the user. The fresnel lens 4 may be positioned on any of the electrodes 32 and may be formed on the electrodes 32 by nanoimprint lithography.

The first transparent body 10, the second transparent body 20 and the at least one lenticular foil 30 are preferably prefabricated elements which are assembled to form the electro-active lens 1. During assembly, the position of the at least one lenticular foil 30 relative to the first and second

transparent bodies

10, 20 can be aligned such that the optical axis O3 is positioned relative to the common optical axis in a manner corresponding to the requirements of the user of the electro-active lens 1. The first transparency 10 and the second transparency 20 are joined by applying an adhesive between the two elements. To this end, the at least one lenticular foil 30 comprises a glue channel 70 through which glue channel 70 an adhesive will be applied joining the first and second

transparent bodies

10, 20. The adhesive may be, for example, a UV curable acrylate type adhesive such as NOA74 or NOA 164.

In order to electrically couple the electrodes 32 to a voltage source (not shown) preferably mounted near the spectacle frame 2, on the spectacle frame 2 and in the spectacle frame 2, there are several electrical connections 8. The electrical connection 8 comprises a conductive layer 33 and a conductive plug 34. The conductive plug 34 has a plug axis 55 and is preferably arranged such that said plug axis 55 is substantially perpendicular to the upper surface of the lens element 21 and/or the lower surface of the lens element 11. Further, the thickness of the plug 34 in the axial direction is a multiple of the thickness of the electrode 32, for example, 20 to 50 times the thickness of the electrode. A conductive layer 33 is disposed on each electrode 32, and because the electrodes 32 may have a relatively small thickness, e.g., about 100nm, it may be difficult to establish a reliable electrical connection (without the conductive layer 33) between the electrodes 32 and the conductor (or conductive plug 34). For example, when the conductor is disposed through the electrode 32 in the axial direction of the electro-active lens 1, the conductor may have only 100nm to be coupled with the electrode 32. Therefore, in order to increase the connection thickness, a conductive layer 33 is provided on the electrode 32. Thus, the conductive layer 33 increases the thickness available for electrically coupling such conductors to the electrodes 32. In other words, due to the conductive layer 33, the total area to establish an electrical connection between the electrode 32 and the conductor (or conductive plug 34) is increased because current is allowed to flow from the conductor (or conductive plug 34) to the electrode 32 via the conductive layer 33. For this reason, the conductive layer 33 preferably has a thickness greater than that of the electrode 32.

Furthermore, the conducting layer 33 may be provided with a conducting plug 34, which conducting plug 34 is arranged in electrical contact with the conducting layer 33 and may be adapted as a basis to which the terminal may be electrically coupled. According to an aspect of the present disclosure, as disclosed in fig. 11, the first and second conductive plugs 34 enclose an angle of less than 120 degrees, preferably less than 90 degrees, for example at most 60 degrees, with each other with respect to an optical axis through the fresnel lens. In other words, as clearly shown in fig. 11, the conductive plugs 34 for a single lenticular foil or lenticular foil stack are arranged on the same side. When viewed in a direction parallel to the optical axis, and when the lens foils are arranged in a manner integrated into eyeglasses, the conductive plugs are arranged laterally, rather than at positions below or above the optical axis. The conductive plugs may be mutually arranged in a manner that is efficient for assembly. For example, the conductive plugs may be arranged in a line. In the case of more than two conductive plugs, they may alternatively be arranged in a small array.

The conductive layer 33 may be a continuous layer formed of a conductive paste (e.g., silver ink paste). However, it is further preferred that the conductive layer 33 is formed such that the visual impact on the electro-active lens 1 is minimized. This may be achieved by shaping the conductive layer 33 as follows: a mesh layer, a layer having one or more holes, a layer comprising a plurality of sub-layers arranged adjacently, any combination thereof, and the like.

In order to reduce the risk of the electrodes 32 being short-circuited to each other via the conductive plugs 34 and/or the conductive layer 33, the regions of the electrodes arranged on opposite positions of the at least one lenticular foil 30 may be removed in the connection regions 36. For example, in the connection area 36, wherein the lower electrode is coupled to the conductive layer 33 and the conductive plug 34 corresponds to an area of the upper electrode on the opposite side of the at least one lens foil 30. The upper electrode and the lower electrode are configured to receive different voltages, and thus an electrical connection between the two should be prevented. To this end, the upper electrode 32 is removed in the connection region 36, wherein the conductive layer 33 and the conductive plug 34 are coupled to the lower electrode 32.

The connection area 36 may be selected such that the electrical connection 8 is in a position of the spectacle frame 2 that minimizes the visual impact on the electro-active lens 1, as explained with respect to fig. 1A and 1B. In a front view of a lens, such as in fig. 1A and 1B, the connection region 36 may be only a relatively small portion of the electro-active lens 1. Therefore, a part of the opposite electrode (explained above) in the removal connection region may be only a relatively small part of the opposite electrode 32.

The description above with respect to fig. 2A applies where appropriate to the following figures, and in order not to obscure the disclosure, the description is not repeated for some of these figures, although the same description may apply to these figures.

Fig. 2B and 2C illustrate a method of integrating more than one lenticular foil 30 into two lenticular elements according to a further aspect of the present disclosure. The at least one lenticular foil 30 in fig. 2B and 2C comprises two optically switchable lenses 31, however the disclosure is not limited thereto. In fig. 2A and 2B, the fresnel lens 4 is shown on the upper electrode of the optical device 31, but the present application is not limited thereto. For example, the fresnel lenses 4 may each be arranged on a lower electrode of a respective optically switchable lens 31. Alternatively, one of the fresnel lenses 4 may be arranged on the upper electrode 32, while the other fresnel lens 4 is arranged on the lower electrode 32 of the respective optically switchable lens 31. For example, the first fresnel lens 4 may be arranged on the upper electrode 32 of the upper optical device 31, while the second fresnel lens 4 is arranged on the lower electrode 32 of the lower

optical device

31, 38, or vice versa.

In fig. 2B, the conductive plugs 34 of the lenticular foil 30 are arranged on top of each other in the axial direction of the electro-active lens 1. More particularly, a conductive plug 34 in electrical contact with the lower electrode 32 of the lower optically switchable lens 31 may be arranged below the conductive plug 34 in electrical contact with the lower electrode 32 of the upper optically switchable lens 31. Likewise, a conductive plug 34 in electrical contact with the upper electrode 32 of the lower optically switchable lens 31 may be arranged below the conductive plug 34 in electrical contact with the upper electrode 32 of the upper optically switchable lens 31. Thereby, when coupling a terminal to a conductive plug 34 (explained later), the conductor may be efficiently coupled to two conductive plugs arranged on top of each other, since only one conductor may be needed to provide the same voltage for both the lower electrode 32 of the lower optically switchable lens 31 and the lower electrode 32 of the upper optically switchable lens 31. Likewise, one conductor may provide two conductive plugs arranged on top of each other, since only one conductor may be needed to provide both the upper electrode 32 of the lower optically switchable lens 31 and the upper electrode 32 of the upper optically switchable lens 31.

Fig. 2C includes the same elements as fig. 2B. However, in fig. 2C, the conductive plugs 34 of the upper and

lower optics

31, 38 forming the at least one lenticular foil 30 are not arranged above each other compared to fig. 2B. This may be beneficial if independent control of the

optical devices

31, 38 is required.

Although the illustrative embodiments of fig. 1, 2A, 3A, 4-11 show only one lenticular foil 30, two or more lenticular foils 30 may be used in these embodiments.

Fig. 3A and 3B show the lens stack from a side view and a top view, respectively. As is evident from fig. 3A, the lens stack formed by the elements discussed with respect to fig. 2A is an unfinished stack. The circular shape of the electro-active lens 1 as shown in fig. 3A (top view) will be edged as will be discussed later to mount the spectacle frame 2.

Fig. 3A is an exemplary view of the positions of the components of the electro-active lens 1. After joining the components as shown in fig. 2A, the first transparency 10 and the second transparency 20 are joined by an adhesive 7 applied in the glue channel 70. In addition, the peripheral edge of the at least one lenticular foil 30 may be surrounded by the adhesive 7. In this example, the fresnel lens 4 is located in the center of the electro-active lens 1 and the conductive plug 34 is located at an outer position of the electro-active lens 1 (as is evident from the top view). After edging this electro-active lens 1, an electro-active lens 1 as in fig. 1A can be obtained. The first transparency 10 and the second transparency 20 can have a circular shape as shown in top view prior to trimming. The first transparent body 10 and the second transparent body 20 can have similar or identical diameters. In the example of fig. 3A, the diameter of the second transparent body 20 is shown to be slightly larger than the diameter of the first transparent body 10. Thus, the outer edge 60 of the entire unfinished electro-active lens 1 is defined by the outer edge of the second transparent body 20. Due to the adhesive 7, the at least one lens foil 30 will be sealed with respect to the environment to ensure a high reliability of the electro-active lens 1.

Fig. 3B shows an example in which two lenticular foils 30 are integrated in the electro-active lens 1. The first and second

conductive plugs

34A, 34A of the upper switchable electro-active lens 31 and the first and second

conductive plugs

34B, 34B of the lower switchable electro-active lens 1 are shown. The position of the first upper conductive plug 34A may coincide with the position of the first lower conductive plug 34A; the same applies to the positions of the second upper conductive plugs and the second lower conductive plugs. In other words, in a top view, the positions of lower conductive plug 34A and lower conductive plug 34B may both correspond to first position 39A. Alternatively, the position of upper conductive plug 34A and the position of lower conductive plug 34B may not coincide, or vice versa, for example, when the position of upper conductive plug 34A corresponds to first position 39A and the position of lower conductive plug 34B corresponds to the second position. In some embodiments, an optional transparent layer 9 may be placed between the lenticular foil 30 and the lower lenticular foil 38. However, in other embodiments, the lower portion of the upper lenticular foil 30 is disposed directly on the lower lenticular foil 38.

Fig. 4A to 4D illustrate a method of producing an electro-active lens. After the stack of three elements has been glued together with an adhesive to obtain an unfinished electro-active lens 1, the electro-active lens 1 is further modified to be incorporated in an eyeglass frame 2, as shown in fig. 3A. In order to align the liquid molecules in the optical device using an electric field, the electrodes 32 are to be coupled to a voltage source (not shown) arranged outside the electro-active lens 1. To this end, in a first step (the result of which is shown in fig. 4A), holes are drilled in the first transparent body 10 and in the at least one lenticular foil 30 in connection areas 36 corresponding to the positions of the conductive plugs 34. Preferably, the hole extends through the entire axial length of the conductive plug 34, and likewise, a hole may also be drilled in the second transparent body 20. As shown in fig. 4A, a hole is drilled in the axial direction of the electro-active lens 1. Furthermore, it is also possible to remove a portion in the radial direction of the first transparent body in a region adjacent to the connection region to allow a conductor to be arranged there.

Fig. 4B shows the electro-active lens 1 after the second step, wherein the side of the electro-active lens 1 is edged to conform to the shape of the spectacle frame 2 where the electro-active lens 1 is to be arranged. For this, the side of the electro-active lens 1 is edged into the peripheral shape of the electro-active lens 1. As will be explained later, the adhesive 7 is preferably applied along the cut-out area (i.e., the area having a shape corresponding to the eyeglass frame 2 in which the electro-active lens 1 is to be placed). Thus, the edging step removes the first transparent body, the second transparent body and the portion of the at least one lenticular foil outside the cut-out area. In this way, the part of the at least one lenticular foil 30 remaining after this step is surrounded by the adhesive 7. As will be understood by those skilled in the art, the first and second steps may be performed in any order or simultaneously.

Fig. 4C shows the result of a third step, the step of coupling terminal 5 to conductive plug 34. The terminals 5, which are coupled to a voltage source arranged near the eyeglasses frame 2, on the eyeglasses frame 2 and/or in the eyeglasses frame 2, are electrically coupled to the connection elements 35, the connection elements 35 being electrically coupled to the conductive plugs 34. The connection element 35 may be formed of conductive silver paste or the like. Thereby, an electrical connection is obtained between the terminal 5 and the transparent electrode 32 via the connection element 35, the conductive plug 34, and the conductive layer 33. The connecting element 35, the conductive plug 34, the conductive layer 33 and the conductor 5 can thus fulfill the function of the electrical connection 8. The terminal 5 may be provided with an insulating layer 51. The insulating layer 51 may prevent accidental electrical conduction due to, for example, weather conditions. In this way, the insulating layer 51 is preferably formed at least in a portion of the conductor 5 that would otherwise be exposed to external conditions. The insulating layer 51 may also cover a larger portion of the conductor 5 as long as at least a portion of the conductor 5 is in electrical contact with the electrical connection 35.

In a fourth step, the passivation layer 6 is applied in the region corresponding to the position of the conductor 5 to restore the substantially concave surface 12 of the first lens element 11. Preferably, the passivation layer 6 is made of a material having substantially the same optical properties as the first lens element 11. Although only one optically switchable lens 31 is shown in the illustrative example of fig. 4A to 4B, the skilled person will appreciate that more than one optically switchable lens 31 may also be present as the at least one lenticular foil 30 in a similar manner.

Fig. 5A-5D illustrate a method of producing an electro-active lens according to another aspect of the present disclosure. The method of establishing the electrical connection 8 as discussed above is similar to the method shown in fig. 5A to 5D. However, the method shown in fig. 5A to 5D applies the electrical connections 8 (e.g. conductive elements) in a lateral direction of the electro-active lens 1, and therefore similar elements discussed in accordance with fig. 4A to 4D are applied to fig. 5A to 5D. Thus, holes or cavities are created from the lateral sides and extend to the axial surface of the conductive plugs.

Similar to the second step discussed with respect to fig. 4B, the unfinished electro-active lens 1 is preferably edged, resulting in an electro-active lens 1 as in fig. 5A. The electro-active lens 1 is edged according to the cut-out area. Thereby, the remaining part of the at least one lenticular foil 30 is surrounded by the adhesive 7.

In a second step, holes are drilled in the electro-active lens 1 in the radial direction of the electro-active lens 1 in the radial connection regions 50 corresponding to the positions of the conductive plugs 34. This step is similar to the first step discussed with respect to fig. 4A, with the difference that the connection region 50 is in the radial direction, whereas the connection region 36 is in the axial direction of the electro-active lens 1. Holes in the connection region 50 are provided onto the conductive plugs 34 and/or into the conductive plugs 34 to electrically couple the conductors 5 with the conductive plugs 34.

In a third step, the conductor 5 is coupled to the conductive plug 34. For example, a connecting element such as silver paste may be provided to electrically couple the conductive plug 34 to the conductor 5.

In a fourth step of producing the device as shown in fig. 5D, a passivation layer 6 is added in the radial connection region 50 to protect the switchable electro-active lens 31 from the external environment and to reduce the optical impact of the connection in the radial connection region 50.

To couple two or more optical devices 31 using a radial connection 50 as shown in fig. 5A to 5D, a configuration of at least one lenticular foil 30 as shown in fig. 2B may be used. Thereby, the two electrodes 32 of the two optically switchable lenses 31 may be coupled to one conductor 5.

Fig. 6 shows an eyeglass frame 2 and an unfinished electro-active lens 1 having an outer edge 60 before edging as discussed according to fig. 4 and 5. The unfinished lens 1 is edged so that the electro-active lens 1 is formed according to a cut-out shape 61 corresponding to the shape of the frame 2. The first lens element 11 and the second lens element 21 are preferably aligned such that their optical axes are aligned on a common optical axis O4. The common optical axis O4 is preferably positioned relative to the pupil position 3 of the user's pupil to correct the user's vision in a suitable manner. Since this relative alignment in a suitable manner may vary from user to user, cut-out shape 61 may be determined according to the needs of the user and the user's choice for a particular frame. After the determination is performed, the cut-out shape 61 is determined. The at least one lenticular foil 30 is preferably prefabricated. However, as described above, cut-out shape 61 may differ among users. Thus, some steps may be required before the other assembly processes discussed in fig. 4 and 5, the at least one lenticular foil 30 may be pre-treated to be bonded between the first and second transparent bodies.

Fig. 7 shows at least one lenticular foil 30 manufactured in advance. In the at least one lenticular foil 30, the at least one lenticular foil 30 may be provided with glue channels 70 before being incorporated into the first and second transparent bodies. These glue channels 70 are arranged along the periphery of the cut-out area 61. Between the gluing channels 70, the plurality of connecting portions 71 may not be cut out to couple an area of the at least one lenticular foil 30 within the cut-out area 61 with an area of the at least one lenticular foil 30 outside the cut-out area 61. Furthermore, in some embodiments, the at least one lenticular foil 30 may be provided with one or more alignment holes 40 at this stage prior to integration between the first and second transparent bodies, which will be discussed later. The connecting portion 71 preferably has a relatively small width while still connecting the portion of the at least one lenticular foil 30 within the cut-out area 61 and the portion of the at least one lenticular foil outside the cut-out area 61. The adhesive 7 to be applied in the glue channel 70 will seal the at least one lens foil 30 with respect to the environment to ensure a high reliability of the electro-active lens 1, the connection portion 71 being configured such that the sealing is reliable, e.g. due to its relatively small width.

The at least one lenticular foil 30 comprises an optically switchable lens 31, which optically switchable lens 31 comprises a fresnel lens 4. The fresnel lens 4 has a third optical axis O3. The third optical axis O3 may have to be aligned with respect to the common optical axis O4. In this case, it is desirable to determine cut-out region 61 prior to providing glue channel 70 and/or alignment hole 40. Thus, the glue channel 70 and/or the alignment hole 40 may be provided in the third optical element 30 such that the optical axis O3 will be aligned with respect to the common optical axis O4 in a manner corresponding to the needs of the user.

Fig. 8 shows how the at least one lenticular foil B is aligned with respect to the first transparent body a and the second transparent body a. The first and second transparent bodies a, a are shown with a peripheral edge 60. The area corresponding to cut-out area 61 is also shown. In step C, the first transparent body a and the second transparent body a are aligned with respect to the at least one lenticular foil B, herein the stack formed by the first transparent body, the second transparent body and the at least one lenticular foil is further modified as discussed according to fig. 4 and 5. The result is an electro-active lens D. As indicated by D, the common optical axis O4 coincides with the optical axis O3 of the fresnel lens 4 of the at least one lenticular foil. In some embodiments, the user may require a lens action of the fresnel lens 4 at another position relative to the common optical axis O4 of the first and second transparent bodies, or in other words, in some embodiments, the third optical axis O3 and the common optical axis O4 need to be spaced apart from each other. This can be achieved by selecting the cut-out area as indicated by B to obtain the electro-active lens 1 as indicated by E accordingly.

Fig. 9 shows how at least one lenticular foil 30 comprising glue channels 70 is incorporated into the first and second

transparent bodies

10, 20. The cut-out regions 61 in the first and

second transparencies

10, 20 are illustrated as examples. The glue channels 70 are arranged in said cut-out areas in the at least one lenticular foil 30.

Fig. 10 shows a method of aligning a first transparent body 10, a second transparent body 20 and at least one lenticular foil 30 to each other using an alignment device. Each of the first transparent body 10, the second transparent body 20 and the at least one lenticular foil 30 is provided with an alignment hole 40 at a suitable location. Alignment holes 40 are provided outside of cut-out region 61, and as such alignment holes 40 are arranged in positions to be cut out during the assembly process as discussed with respect to fig. 4 or 5. Or in other words, the alignment holes are provided at positions arranged outside the area surrounded by the glue passage 70. The first transparent body 10, the second transparent body 20 and the at least one lenticular foil 30 are aligned with alignment pins 41 inserted into the alignment holes 40. The alignment holes 40 have substantially the same diameter and cross-sectional shape as the alignment pins 41. Thereby, if the alignment pin 41 is inserted into the hole 40 of the component, the component is prevented from moving in the radial direction with respect to the alignment pin 41. By using two or more pins 41, the element cannot move relative to the alignment pins 41. The mutual alignment of the components can thereby be achieved precisely.

Fig. 11 shows a further cross-sectional view and a top view of the finished electro-active lens 1. Due to design variability of the present disclosure, the electrical connections 8 including the terminals 5, the electrical connections 35, the conductive plugs 34, and the conductive layer 33 may be disposed relatively close to each other in the finished electro-active lens 1.

Fig. 12A and 12B show another embodiment of an electro-active lens 1 according to an embodiment of the present disclosure, for example an electro-active lens as manufactured by a method according to the present disclosure.

In the previous embodiment of the device, the optical device 31 in which the conductive plug 34 was previously provided has been discussed. For the purposes of this disclosure, proper placement of the conductive plug 34 may be relevant. In fig. 12, the electro-active lens 1 comprises a conductive plug 34 exposed outside the lens, thereby providing a contact surface that makes it easier to provide a suitable area for contact with an external conductor.

In some of the previously described embodiments of the method for manufacturing, an opening or hole is provided in the electric lens 1 to facilitate electrically coupling any external conductor with the conductive plug 34. However, in other embodiments, such openings may be omitted.

For example, an embodiment of a method for manufacturing according to the present disclosure may include (at least) the steps of:

similar to the previously discussed embodiments, the optical device 31 comprising the Fresnel lens 4 is placed between the

lens elements

11, 21 at a location appropriate for a particular user. Thus, the desired position may again depend on, for example, the pupil of the user and the actual glasses to which the lens elements are to be mounted.

As a first step, the appropriate position of the fresnel lens 4 in the electro-active lens 1 is determined. This may be determined in a manner similar to that of fig. 6.

Determining one such appropriate position also automatically determines the cut-out area of the optical device 31. That is,

lens elements

11, 21 will be cut or edged in such a way that: the cutting makes the lens element suitable for the actual spectacles in which the electro-active lens 1 is to be mounted. An optical device 31 is arranged between said

elements

11, 21.

In order to manufacture the electro-active lens 1 as shown in fig. 12, the conductive plug 34 should be arranged at the boundary of the previously determined cut-out region 61 in the optical device 31. Thus, before gluing the optical device 31 between the first lens element 11 and the second lens element 21, said optical device 31 is opened again and one or more, preferably two, conductive plugs 34 are arranged on the border of the cut-out area. However, typically the lens does not have completely flat side surfaces as shown for the electro-active lens 1 in fig. 12. For example, the lens may be provided with a bevel as an additional thickening on the edge of the lens, which bevel typically extends over substantially the entire circumference of said lens. In an embodiment of the present disclosure, the slope is partially removed to locally realize a flat side surface to accommodate and expose the conductive plug 34. For example, partial removal of the bevel may be achieved by milling or similar operations.

By means of said additional milling it is possible to locally remove the entire bevel and provide a completely flat side surface, similar to the side surface shown in fig. 12. In other embodiments, it may be sufficient to remove only a portion of the bevel.

Regardless of how much lens material of the bevel is removed, upon further milling of the electro-active lens, the conductive plug 34 should preferably be placed outside the initially cut boundary 61, slightly inward in the radial direction of the lens. That is, the plug 34 should be positioned at a distance from the initial cut boundary 61 that corresponds to the amount of bevel that will be removed, which ensures that the conductive plug 34 is properly exposed after the additional milling.

After arranging the conductive plug 34 in the optical device 31, the device is arranged between and glued to the

lens elements

11, 21, for example in accordance with the process described with respect to fig. 2A.

Fig. 13A and 13B (in exploded and sectional views, respectively) show an embodiment of a protective body 47 for an external connector as mentioned in the context of fig. 12A and 12B. The external connector 47 provides an electrical connection between the exposed conductive plug 34 of the embodiment of fig. 12A and 12B (the conductive plug 34 is not shown in fig. 13A and 13B) and the further electronic device that is part of the electronic eyewear, as the external connector 47 includes the conductor 46. The conductor 46 may be formed, for example, by curing silver ink on the side of the electric lens. The protective body 47 is configured to protect the conductive body 46 from external influences such as moisture and/or impact. The protective body 47 may be shaped to at least partially surround the protective body 47 and/or may be made of a material having more elastic and waterproof properties (e.g., rubber). In the case of silver ink, the protective body 47 may also help to hold the ink in place as it cures.

It is to be understood that this disclosure is not limited to the particular aspects described, and as such may vary. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only, and is not intended to be limiting, since the scope of the present disclosure will be limited only by the appended claims.

List of reference numerals:

1 electro-active lens

2 spectacle frame

Pupil of the user

4 Fresnel Structure

5 terminal

6 passivation layer

7 adhesive

8 Electrical connection

9 transparent layer

10 first transparent body

11 first lens element

12 convex surface first transparent body

13 flat surface first transparent body

20 second transparent body

21 second lens element

22 concave surface second transparent body

23 flat surface second transparent body

30 at least one lenticular foil

31 optical device

32 transparent electrode

33 conductive layer

34 conductive plug

35 connecting element

36 connection region

37 volume

38 lower optical device

39 conductive plug position in top view

40 aligned with the hole

41 alignment pin

42. 43 holes or cavities

44. 55 shaft of conductive plug 34

46 conductive body

47 protective body

50 radial connection zone

51 insulating layer

60 outer region of the first or second transparency prior to trimming

61 cut out region

70 gluing channel

71 connecting part

O1 first optical axis

O2 second optical axis

O3 third optical axis

O4 common optical axis

Claims

1. A lenticular foil comprising a first substrate having a first transparent electrode, a second substrate having a second transparent electrode, and a Fresnel lens and a liquid crystal material located between the transparent electrodes, wherein the transparent electrodes, the Fresnel lens and the liquid crystal material define an optical device having an optical axis in at least one state of the optical device,

wherein the lenticular foil further comprises a first conductive plug and a second conductive plug extending through the lenticular foil,

wherein the first and second conductive plugs are positioned relative to an optical axis of the Fresnel lens such that radial lines extending from the optical axis to the first and second conductive plugs enclose an angle of less than 120 degrees, preferably less than 90 degrees, more preferably less than 60 degrees with each other.

2. The lenticular foil of claim 1, further comprising:

-a first conductive layer disposed on and electrically coupled to the first transparent electrode, an

A second conductive layer disposed on and electrically coupled to the second transparent electrode,

wherein the first and/or second conductive layers have a greater thickness in an axial direction of the lens than the first and/or second transparent electrodes, and wherein the first and/or second conductive layers are electrically coupled to first and/or second conductive plugs, respectively.

3. Lenticular foil according to claims 1 to 2, wherein no part of the first and/or second transparent electrode is present in the area between the fresnel lens and the first and/or second conductive plug, and/or wherein the conductive plugs (34) each have a plug axis (55) extending substantially perpendicular to the transparent electrodes (32), and/or wherein the thickness of the conductive plugs (34) in the plug axis direction is a multiple of the electrode thickness of at least one of the electrodes, for example 20 to 50 times the electrode thickness.

4. A stack of a first lenticular foil and a second lenticular foil according to any one of the preceding claims, and wherein preferably the liquid crystal material of the first lenticular foil and the second lenticular foil is a nematic liquid crystal material, and wherein the optical arrangement of the first lenticular foil is oriented at a 90 degree angle with respect to the optical arrangement of the second lenticular foil.

5. The stack of claim 4, wherein the conductive plugs of the first and second lenticular foils are oriented such that the axes of the first conductive plugs of the two lenticular foils are aligned, and wherein preferably the first conductive plugs are electrically connected to each other.

6. A method of manufacturing an electro-active lens system forming a stack of at least three elements, the stack comprising a first transparent body, a second transparent body and a lens foil or a stack of lens foils according to any one of the preceding claims 1 to 5, the method comprising the steps of:

-providing at least one lenticular foil on the first transparent body;

-providing the second transparent body on the at least one lenticular foil;

-creating at least one axial surface in the first and second conductive plugs extending at least substantially parallel to a plug axis,

-providing an auxiliary conductive material in direct contact with at least one axial surface of the conductive plug, and

-providing a conductive element configured for transmitting a voltage for operating an optical device connected to the auxiliary conductive material.

7. The method of claim 6, wherein the first and second transparent bodies are lens elements having a first and a second optical axis, respectively, which are aligned on a common optical axis, wherein the lens foil is assembled to the transparent bodies such that the position of the optical axis of the at least one lens element is different from the common optical axis in a radial direction of the optical device.

8. The method of any one of claims 6 to 7, wherein the step of creating the axial surface comprises the steps of:

-removing a portion of at least one of the first and second transparent bodies in a connection region, thereby exposing the first and/or second conductive plugs;

-creating a hole in at least one of the first or second conductive plugs to define an annular surface, the annular surface being the axial surface;

wherein preferably the auxiliary conductive material at least partially fills the hole and at least a portion of the conductive element is arranged at an exposed major face of the first or second transparent body, at least a portion of the conductive element being coupled to the auxiliary conductive material at the exposed major face.

9. The method of any of claims 6 to 7, wherein the step of creating the axial surface comprises:

-producing a hole in the at least one lenticular foil, the hole extending into the first and/or second transparent body, being oriented transversely with respect to the plug axis, and terminating in the first or second conductive plug, thereby defining the axial surface,

wherein preferably the conductive element is partially disposed in the aperture and is connected to the conductive plug by the auxiliary conductive material.

10. The method of any of claims 6 to 9, further comprising:

-applying a gluing channel into the at least one lenticular foil in at least one gluing zone along an edge of the cut-out area, the gluing channel extending from a first main face to an opposite second main face of the at least one lenticular foil, and

-filling the glue channel with an adhesive to provide an adhesive connection between the first and second transparent bodies.

11. An electro-active lens system forming a stack of at least three elements, wherein a lens foil or stack of lens foils according to any one of claims 1 to 5 is sandwiched between a first and a second transparent body,

wherein the conductive plugs have plug axes extending substantially perpendicular to the transparent electrodes, and each of the conductive plugs is provided with an axial surface extending at least substantially parallel to the plug axes, at which axial surface the conductive plugs each contact an auxiliary conductive material connected to a conductive element extending out of the stack.

12. The electro-active lens system of claim 11, wherein the first and second transparent bodies each have an optical axis mutually aligned on a common optical axis, and wherein the optical axis of the at least one lens foil is arranged different from the common optical axis, wherein preferably the optical axis of the at least one lens foil is oriented parallel to the common optical axis but laterally offset from the common optical axis.

13. The electro-active lens system according to any one of the preceding claims 11-12, wherein the axial surface is an annular surface, and wherein the auxiliary conductive material extends in an axial direction, not only within the annular surface, but through at least one of the first and second transparent bodies to an outer surface thereof, where it is connected to the conductive element.

14. The electro-active lens system of any one of claims 11 to 12, wherein the auxiliary conductive material extends laterally from the axial surface, preferably within a conductor channel in which a portion of the conductive element can also be present.

15. A pair of spectacles comprising at least one electro-active lens system according to claims 11 to 14, preferably further comprising a controller for controlling signals for switching the liquid crystal material within the optical device between at least a first state and a second state.

16. A stack of mutually attached first and second lenticular foils, each comprising a first substrate having a first transparent electrode and a second substrate having a second transparent electrode, with a Fresnel lens and liquid crystal material present between the transparent electrodes, wherein the transparent electrodes, the Fresnel lens and the liquid crystal material define an optical device,

wherein each lenticular foil further comprises a first conductive plug and a second conductive plug extending through the lenticular foil.

17. The stack of claim 16, wherein the liquid crystal material of the first and second lenticular foils is a nematic liquid crystal material, and wherein the optical arrangement of the first lenticular foil is oriented at a 90 degree angle with respect to the optical arrangement of the second lenticular foil.

18. A stack according to claim 16 or 17, wherein the conductive plug (34) has a plug axis extending substantially perpendicular to the transparent electrode (32), and

wherein preferably the conductive plugs of the first and second lenticular foils are oriented such that the axes of the first conductive plugs of the two lenticular foils are aligned, and wherein the first conductive plugs are electrically connected to each other.

19. The stack of claim 18, wherein the axes of the second conductive plugs of the two lenticular foils are aligned, and wherein the second conductive plugs are electrically connected to each other.

20. A stack according to any one of claims 16 to 19, wherein the first and second conductive plugs are positioned relative to an optical axis of the fresnel lens such that radial lines extending from the optical axis to the first and second conductive plugs enclose an angle of less than 120 degrees, preferably less than 90 degrees, more preferably less than 60 degrees with each other.

21. An electro-active lens system forming a stack of at least three elements, wherein the stack of lens foils according to claims 16 to 20 is sandwiched between a first and a second transparent body, wherein the first and second conductive plugs of the lens foils have plug axes, via which the lenses are electrically coupled to conductive elements extending out of the stack.

22. The electro-active lens system of claim 21, wherein the conductive plug is provided with an axial surface at which an auxiliary conductive material is present, the conductive element being connected to the auxiliary conductive material, wherein the auxiliary conductive material extends within a vertically or laterally arranged channel.

23. An electro-active lens system forming a stack of at least three elements, wherein at least one lens foil is sandwiched between a first transparent body and a second transparent body,

wherein the lenticular foil comprises a first substrate having a first transparent electrode and a second substrate having a second transparent electrode, a Fresnel lens and a liquid crystal material being present between the transparent electrodes, wherein the transparent electrodes, the Fresnel lens and the liquid crystal material define an optical arrangement,

wherein the first transparent electrode and the second transparent electrode are each electrically coupled to a conductive element extending at least partially outside the lens system,

wherein the electro-active lens further comprises a first and a second conductive plug extending through the electro-active lens, and each of the conductive plugs is provided with an axial surface extending at least substantially parallel to the plug axis, at which axial surface the conductive plugs each contact an auxiliary conductive material connected to a conductive element extending out of the stack,

wherein the auxiliary conductive material extends transversely within the conductor channel from the axial surface, wherein preferably also a part of the conductive element is present within the conductor channel.

24. A method of manufacturing an electro-active lens system, the lens system forming a stack of at least three elements, the stack comprising a first transparent body, a second transparent body and at least one lens foil, the lens foil comprising a first substrate having a first transparent electrode and a second substrate having a transparent electrode, a fresnel lens and a liquid crystal material being present between the transparent electrodes, wherein the transparent electrode, the fresnel lens and the liquid crystal material define an optical arrangement, the lens foil further comprising a first conductive plug and a second conductive plug extending through the lens foil, the method comprising:

-providing the at least one lenticular foil on the first transparent body;

-providing the second transparent body on the at least one lenticular foil;

-providing an auxiliary conductive material directly contacting the at least one axial surface of the conductive plug and connected to a conductive element electrically coupling the first and second transparent electrodes to the conductive element, the conductive element configured for transmitting a voltage for operating the switchable lens,

wherein the step of creating the axial surface comprises: creating a hole in the at least one lenticular foil, the hole extending into the first and/or second transparent body, being oriented transversely with respect to the plug axis, and terminating in the first or second conductive plug, thereby defining the axial surface,

25. The system of claim 23 and method of claim 24, wherein the conductor channel has a substantially cylindrical shape.

26. The system of claim 23 and method of claim 25, wherein the conductor channel is at least partially shaped as a truncated cone.

27. The system and system according to claims 23-27, wherein the conductive plug (34) has a plug axis extending substantially perpendicular to the transparent electrode (32).

28. The system and method of claim 27, wherein the conductor channel is arranged perpendicular to the plug axis.

29. The system and method of claim 27, wherein the conductor channel is arranged at an oblique angle to the plug axis.

30. A method of manufacturing an electro-active lens system, the lens system forming a stack of at least three elements, the stack comprising a first transparent body, a second transparent body and at least one lens foil, the lens foil comprising a first substrate having a first transparent electrode and a second substrate having a transparent electrode, a fresnel lens and a liquid crystal material being present between the transparent electrodes, wherein the transparent electrode, the fresnel lens and the liquid crystal material define an optical arrangement, the lens foil further comprising a first conductive plug and a second conductive plug extending through the lens foil, the method comprising:

-providing the at least one lenticular foil on the first transparent body;

-providing an adhesive on the at least one lenticular foil;

-providing the second transparent body on the at least one lenticular foil, wherein the adhesive is arranged between the at least one lenticular foil and the second transparent body;

wherein the at least one lenticular foil is provided with at least one glue channel extending through the lenticular foil to extend from the first transparent body to the second transparent body after manufacture, wherein the adhesive is provided in the glue channel and cured to constitute an adhesive connection.

31. The method of claim 30, wherein the at least one glue channel is disposed outside an area defining the optical device.

32. The method of claim 31, further comprising the steps of: the shape of the electro-active lens system is modified such that the glue channel filled with adhesive becomes part of the peripheral edge of the at least one lens foil.

33. The method of claim 32, wherein there is at least one connection region extending outwardly from a cut-out region defined by at least one glue channel away from a region defining the optical device.

34. The method of claim 33, further comprising the steps of: the at least one lenticular foil is aligned with at least one of the first and second transparent bodies and/or a further lenticular foil by an alignment means in the connection area, wherein the alignment means is, for example, at least one alignment hole.

35. The method according to any one of claims 30 to 34, wherein the conductive plug (34) has a plug axis extending substantially perpendicular to the transparent electrode (32), the method further comprising the steps of:

-creating at least one axial surface in the first and second conductive plugs extending at least substantially parallel to the plug axis,

-providing an auxiliary conductive material directly contacting the at least one axial surface of the conductive plug and connected to a conductive element configured for transmitting a voltage for operating the switchable lens to electrically couple the first and second transparent electrodes to the conductive element.

36. The method of claim 35, wherein the step of creating the axial surface comprises: creating a hole in the at least one lenticular foil, the hole extending into the first and/or second transparent body, being oriented transversely with respect to the plug axis, and terminating in the first or second conductive plug, thereby defining the axial surface,

37. An electro-active lens system forming a stack of at least three elements, wherein at least one lens foil is sandwiched between a first transparent body and a second transparent body, and wherein the at least one lens foil comprises a first substrate with first transparent electrodes, a second substrate with second transparent electrodes, and a Fresnel lens and a liquid crystal material between the transparent electrodes, wherein the transparent electrodes, the Fresnel lens and the liquid crystal material define an optical arrangement, wherein the first and second transparent electrodes are each electrically coupled to conductive elements extending at least partially outside the lens system,

wherein preferably each of said conductive plugs is provided with an axial surface extending at least substantially parallel to a plug axis at which said conductive plugs each contact an auxiliary conductive material connected to a conductive element extending outside said stack,

wherein there is an adhesive connection extending from the first transparent body to the second transparent body or along a peripheral edge of the at least one lenticular foil through an adhesive channel.

38. The electro-active lens system of claim 37, wherein said auxiliary conductive material extends laterally from said axial surface within a conductor channel in which preferably also a portion of said conductive element is present.